I use the metal under the drivers legs with the crossbar as a jack point. I marked it just to the inside of the fiberglass on the bottom of the car. It works good, and you don't have to be perfectly on the bar. You will need something like this to get a low profile jack under it. Its what I have been using without any problems.
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1 Make sure they are the ones without the "1.5" Stop ridge" on the end. You want the flat top ones because the front splitter could hit the Stop Ridge on the other ones.
I also can just jack up the rear by going under the rear diffuser and a little past the flat bottom aluminum piece to a bar under the trans. I don't need any ramps in place for that. You can do it on the front also, but you will need the ramps on and the jack will have to be low to clear the race splitter. I lift the main bar a little back and below of the steering rack. You just have to be really careful with the jack handle when lowering. It need to be horizontal.